Nitro-substituted diisocyanate compounds



, 2,978,475 o-s'UBsriTUrEn nnsocYANArE COMPOUNDS Kari Klager, Monrovia,Califl, assignor to Aerojet-Qeneral Corporation, Azusa, Califl, acorporation of Gino No Drawing. Filed Mar. 26, 1956,Ser. No. 574,035

I 8 Claims. ((31. 260 -453) This invention relates to new compositionsof matter and in particular to a new class of nitro-substituteddnsocyanate compounds having the general formula:

wherein A and A are lower alkylene radicals. .This'application is acontinuation-in-partof my copending US. patent application Ser. No.397,017, filed December 8, 1953, now abandoned.

The new compositions of my invention are prepared by reacting a dibasicacid halidejwith an alkali metal or alkaline earth metal azide to formthe corresponding di az'rd'e compound and subsequently heating thediazide compound to eir'ectfre'arrangement to the desired diisocyanate..The reaction proceeds. according to'the :gen-

e'ral reaction scheme set forth below.

wherein is a halogen radical andA andA" are lower alkylene radicals.vThe az-ide salt employed in this procedure can be any ot the alkalior-alkaline earth metal el d ch rnta s um .azide,, sne i with o th l k wv r; s um ends i e pre e e antg the practice of this invention forreasons of cost'and convenience. The diacid halide compounds used asstarting materials in the practice of this invention are prepared fromthe corresponding diecid compounds in the conventional manner, forexample by reaction with P01 or PBr The diacids are obtained by theprocedure dis- "closed in my copending U.S. patent application Ser. No..

, 392,479, filed November 16, 1953, now abandoned.

The following examples are presented to more clearly illustrate myinvention, it should be understood however that these examples areprovided solely for the purpose, of illustration and should not beconsidered to limit the scope of the invention in any way.

EXAMPLE I U chloride A mixture of- 14 gm.4,4,6,6,8,-8-hexanitro'-1,1l-undecanedioic acidjsand 40 ml. phosphorusoxychloridew'as allowed to reactgradually with"19 gm. phosphorus penta-jchloride. The temperature. rose to C;' the mixture I l was thenheatedxto80C for 15 minutes. The phos- 13.55. Found: Percent C,

Patented Apr. 4, 1961 phorus oxychloride was removed fromthe solutionunder vacuum until vcrystals appeared, and 30 benzene was added-tocompletecrystallization. 1 The crystals were collected and washedwith'he'xane and absolute ether; yield was 8.4 gm, Hexane .causedprecipitation of a second fraction, which was filtered off and washedwitl1 4.6

gm. of absolute ether. The total yield was 13.0 gm. A

Sample recrystallizedfrom phosphorus oxychloride and in'onochlorobenzene melted at 120421 C; this sample was used for analysis. The mixedmelting point with 4,4 6,8,8-pentanitro-1,ll-undecanedioyl chloride (MP.141' C) was depressed to 110-112" C. p 7 I y I Analysis.Calcd. for C HN3O Cl Percent C, 25.25; percentH, 2.31; percent N, 16.07; percent 01-,I 5.85; percent H, 2.49; er-

cent N, 15.96; percent Cl, 13.25.

EXAMPLE II Preparation of 4,4,6,6,8,8-hexanitro-1 ,11 -undcanedioicazide A mixture of 4 gm. sodium azide in 30 m1. acetic acid waspouredinto a suspension of- 5 gm. 4,4,6,6,8,8-hexani'-tro-Lll-undecanedioyl dichloride in 30 ml. acetic acid at EXAMPLE IIIPreparation of 3,3,5,5,7,7 -hexzznitr0- 1,P-riorzliite Ziii'socy-"dilate A three-necked flask provided; with a stirrer thermo ineterwascharged with liO gm. of 4,4 ,6,6,8,8 hexanitrct- 1,1 l-undec'anedioylchloride and 80 ml. acetic acid and cooled with ice water to 10 C. Eightgm. sodium azide was added at once while the mixture was stirredrapidly. The temperature rose to 22? C. and a milky-white suspension wasformed. Stirring at 15 to 20 C. was continued fee 45 minutes and'themixture was then diluted with 15o hill-methylene chloride. Thesolutions/as their washed in'a separatory funnel twice with two .100 ml.portions of ater, once with aqueous 1%;sodiurn bicarbonate, and

the methylene chloride solution was concentrated in vacuo at roomtemperature; the receiver was cooled with Dry 7 Ice and acetone. The"crystals. formed were precipitated with absoluteether collected on afilter, then washed with absolute ether and replaced in the flask. Ihecrystals" dissolved. easily in 100 ml. dioxane and the solution obtainedwas heated slowly to SO-85 C., using a reflux condenser with Drieritetube. At C. the nitrogen evolution started and was over within 15minutes, at C. Heating'was continued for 1 hour and the solution wasthen concentrated in vacuo. The golden-yellow Preparation of4,4,6,6,8,8-hexanitrb-Z,11-untiecanedioyl residue sooncrystalliZed andwas triturated'with abso- V lute ether. After filtration fand washingwith ether, the.

' 'crystals were reprecipitated repeatedly from a concen trated solutionin dioxane with carbon tetrachloride. The

' melting point .was 126-128" C. I

V Analysis.Calcd. for C H NgQ Percent, C, 27.51;"

percent H, 2.52; percent N; 23.33. Found; Percent C,:

27.78;:percent H, 2.56;percent-N, 23.70.

Other members in the homologous series of'compounds v of thisjinventioncan be prepared by reacting-appropriate .j' starting materials inaccordance with'theforegoing exam once again with'wa'ter, After dryingover sodium sulfate ples. For example, the diacid chloride of6,6,8,8,10,10- hexanitro-1,15-pentadecanedioic acid readily reacts withsodium azide to yield its corresponding diazide, which in turnrearranges through the application of heat to form the desireddiisocyanate compound, 5,5,7,7,9,9-hexanitro-1,l3-tridecanediisocyanate. Other members of this series can bepreparedby the same procedure, starting with ap propriate diacid halides.

The new compositions of this invention are useful in the preparation ofhigh energy polyurethane propellants. For example,3,3,5,5,7,7-hexanitro-1,9-nonane diisocyanate reacts with glycols suchas 2,2-dinitro-1,3-propanediol, 2,2,4,4-tetranitro-l,S-pentanediol and2-nitro-2-methyl-1, 3-propanediol to form high molecular weightpolyurethane compounds. This reaction proceeds under the conditions andaccording to the method disclosed in assignees copending US. patentapplication Ser. No. 422,649, filed April 12, 1954, now abandoned. Thepolyurethanes thus obtained can be molded, cast, or formed into tubularshape and enclosed in a rocket chamber in the conventional manner, forexample as shown in assignees co- -pending US. patent application Ser.No. 516,352, filed June 20, 1955. They are ignited by suitable igniters,

such as the igniter disclosed in ass'ignees copending US. patentapplication Ser. No. 306,030, filed August 23, 1952. Upon exhaustionthrough. a nozzle, the gases produced by the resultant combustion can beused to propel any conventional rocket vehicle such as a guided missile,

wherein A and A are lower alkylene radicals.

2. As a composition of matter, 3,3,5,5,7,7-hexanitro- 1,9-nonanediisocyanate having the structural formula:

3. As a composition of matter, 5,5,7,7,9,9-hexanitro- 1,13-tr1decanediisocyanate having the structural formula:

N0, N0, N0:

- 4 4. The method of preparing diisocyanate compounds having generalfromula:

which comprises reacting the diacid halide composition having thestructural formula:

with an azide salt selected from the group consisting of alkali andalkaline earth metal azides and subsequently pyrolysing the resultantdiacid azide to the desired diiso cyanate, wherein A and A are loweralkylene radicals and X is a halogen radical.

5. The method of preparing 3,3,5,5,7,7-hexanitro-1,9- nonanediisocyanate which comprises reacting a 4,4,6,6,

8,8-hexanitro-l,ll-undecanedioic diacid halide with an nonanediisocyanate which comprises reacting a 4,4,6,6,

OON-CHgCHgCH1OHrC-CHz-C-CHz-C-CHzCHaCHaCHz-NCO8,8-hexanitro-l,1l-undecanedioic diacid halide with an azide selectedfrom the group consisting of alkali and alkaline earth metal azides, ata temperature of from about 10 to about 22 C., and subsequentlypyrolysing the resultant 4,4,6,6,8,8-hexanitro-l,ll-undecanedioic azide,at a temperature of from about to about C., to the desired diisocyanate.

References Cited in the tile of this patent UNITED STATES PATENTS

1. AS COMPOSITIONS OF MATTER, THE HEXANITOR DISCOYANATE COMPOUNDS HAVINGTHE STRUCTURAL FORMULA: